ProjectSummary/Abstract Transitionmetalcatalyzedcrosscouplingisoneofthemostimportantstrategiesin complexmoleculesynthesis.Thisapproachhasbeenwidelyappliedinmedicinaland biological research for drug candidate preparation and for biological target modification/functionalization.Despitethegreatsuccessesduringthelasttwodecades, there are remaining challenges that need to be addressed. The three problems in coupling type transformations that we would like to address in this proposal are A) controlling selectivity on cross coupling while alkynes are involved, B) increasing the efficiency of forming large macrocycles through catalytic coupling process, and C) extending the choice of coupling partners, such as amine and F-, as compatible functional groups for coupling type transformations. The general scheme of the proposedresearchistheligand-assistedgoldredoxcatalysis,recentlydevelopedfrom PI?s lab. Compared with the conventional coupling methods, gold chemistry offers some unique reactivity, including fast reductive elimination, selective formation of gold acetylide and ligand-assisted diazonium activation through nitrogen extrusion. These propertiesprovidenewopportunitiestoaddresssomeofthelong-existingchallengesin metal catalyzed cross coupling. The proposed research is innovative because it focuses on the impact of new reactivity offered by this recently developed Au(I)/Au(III) redox catalysis toward challenging C-C and C-X coupling transformations. These investigations are also significant and will advance pharmaceutical and medicinal researchbyprovidingnewstrategiestoachievecomplexmoleculesynthesis.